Apparatus for coating the interior of well pipes



A. c. CURTIS 2,713,908

APPARATUS FOR COATINO THE INTERIOR OF' WELL PIPES July 26, 1955 2 Sheets-Sheet 1 Filed Feb. 9, 1955 INVENTOR /VAVE4 c. cra/P775,

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ATTORNEY July 26, 1955 A. c. CURTIS 2,713,908

APPARATUS FOR COATING THE 'INTERIOR oF WELL PIPEs Filed Feb. 9, 1955 2 sheets-Sheet 2 ATTORNEY United States Patent O APPARATUS FOR COATING THE INTERIOR OF WELL PIPES Arvel C. Curtis, Odessa, Tex., assignor to Pipelife, Inc., a corporation of Texas Application February 9, 1953, Serial No. 335,858

6 Claims. (Cl. 166-67) The invention relates to the cleaning and coating of the interior of wells, and more particularly to the coating of the inside of the tubing, or of the inside of the casing and the inside and outside of the tubing, of oil wells. It is especially directed to apparatus useful for this purpose.

It is recognized that many liquids which are present in wells either damage the interior of the well by corrosive or other action or are likely to coat the interior and clog up the pipes. It is of course possible to coat the pipe sections internally before they are placed in the wel, but when this is done the joints are not properly coated, and are still subject to attack by the liquids in the Well.

The primary object of the present invention is to provide an apparatus which can be. yused in connection with u the coating of the interior of wells in ground.

Another object of the invention is to provide an arrangement of this type which is of simple construction and which is easy to use in the cleaning and coating operations.

Still another object of the invention is to provide a device by which it is possible to displace the liquid cleaning or coating material downwardly through the well pipe which is being coated, so as to leave a satisfactory smooth even coating on the interior of the pipe.

Still another object of the invention is to provide an apparatus in which, the liquids being displaced from the well by air pressure, the pressure used can be relatively small compared to the head of liquid in the well.

An additional object of the invention is to provide an arrangement which is of simple and light construction, and is easily portable so that it can be carried to wells such as oil and gas wells which are in remote areas.

position in the Further objects and advantages of the invention will appear more fully from the following description, especially when taken in conjunction with the accompanying rawings which form a part thereof.

In the drawings:

Fig. 1 shows in cross-section an apparatus embodying my invention;

Fig. 2 is a top plan view; and

Fig. 3 is a cross-section showing a part of a slightly modified form of apparatus.

The arrangement shown in Fig. l is intended to be used for coating the interior of the tubing 2 of a well having a casing 4.

The apparatus according to the invention resides primarily in a container or expansion chamber 6 of round horizontal cross-section and a similar cover piece 3 forming a second expansion chamber' above the first chamber. The two parts are connected by flanges 10 and bolts 12.

The chamber 6 has a central tubular part 14 extending upwardly therethrough and provided with openings 16 in its side walls. This part also extends downwardly as at 18 to engage over and be threaded on the top of the tubing 2. Aligned with the tubular portion 14 is ya seat 20 having tapered wells for receiving a wedging arrangement 22. This is adapted to hold a pipe 24 of smaller cross-section than the tubing 2, which extends down into the tubing.

Chamber 6 also has lateral openings 26, 28 at opposite sides thereof. It further has at the bottom a drain valve 30.

Upper expansion chamber 8 has extending from its top wall a pipe 32 in alignment with the pipe 24, as well as lateral outlets 34 and 36,'and a pressure gauge 38.

Opening 26 is connected by a pipe 40 containing a valve 42 to a suitable source 44 of cleaning or coating material. Pipe 32 is connected through a valve 46 and a separator 48 to the container 44. Opening 28 is connected through a pipe 50 containing a valve 52 to a compressor 54 or other suitable source of compressed gas under pressure.

In using the apparatus just described, a plug 56 is set in the bottom of the tubing 2, and the lower expansion chamber 6 is threaded on the top of the tubing 2. A screen 58 is provided at the bottom end of the pipe 24 which extends almost down to the plug 56. Tubing 24 is introduced through seat 20 and secured in position by holding member 22. The cap 8 is then secured in position by bolts 12. Pipes 32, 40 and 50 are connected to tank 44 and to compressor 54 in the manner shown.

With valves 52 and 46 closed, and valve 36 open, cleaning material is introduced by pump 6i) through opening 26 and the expansion chamber 6 until it fills the interior of the tubing 2 and of the pipe 24. After the cleaning material has been left for sucient time to loosen the deposits, pump 6() is shut ot, valve 36 is closed, valves 52 and 46 are opened and the compressor 54 is started in operation. Compressed air is then introduced into the chamber 6 through opening 28. This air will push down the liquid standing in the tubing 2, and displace it upwardly through pipe 24. Some of the liquid will collect in chamber 8, while some of it will pass on through pipe 32 to container 44.

When the liquid level reaches the bottom of tubing 2, the air or other gas Will enter the bottom of pipe 24 and move upwardly therethrough. In so doing, it will partially displace upwardly the liquid in the pipe 24 and will partially entrain this liquid. The entrained liquid will be carried out through pipe 32 and valve 46, the air will be removed from it in separator 48 and the material will be collected in container 44.

When all the cleaning material has been displaced, any remaining in chamber 8 can be removed through outlet 34.

When the cleaning has been completed, compressor 54 is stopped and valves 46 and 52 closed. A container of coating material is substituted for container 44, and the same operations are repeated with the coating material. This will leave a layer of coating material behind on the inside of tubing 2, as the material is forced downwardly through this tubing by compressor 54. Such a coating will be smooth and uniform, and of satisfactory thickness.

Fig. 3 shows an arrangement of a similar nature but adapted to be used for simultaneously coating both the interior of a well casing and the exterior and interior of the tubing. In this system, the apparatus is exactly the same except that the tubular section 14 and the downward extension 18 are of such size as to fit over the outside of the casing 4, while the seat 20' will receive a holding member 22' for the tubing 2.

In using this arrangement, the tubing 2 is rst withdrawn from the well, and a plug 56 is set in the casing at the desired depth. The apparatus is then set on top of the casing 4 in the manner described above, the tubing 2 being introduced with a screen 58 at its bottom end.

The cleaning and coating are then carried outin the same manner as described above.

At the end of the operation, it is necessary to remove the tubing 2 to get out the plug 56 and the tubing is then restored tothe well and it is ready for operation,

. While I have described herein some embodiments of my invention, I, wish it to be understood that I do notintend to limit myself thereby except within the, scope of the claims hereto. or hereinafter appended.

I claim:

l. Apparatus for painting the interior of well pipes or the like comprising, in combination, means forming an expansion chamber having an opening in its bottom for receiving the upper en d of a well pipe, the horizontal cross-section of saidchamber being substantially larger than such opening, said chamber having at least one opening into the side thereof, means forming a second expansion chamber above the first chamber and separated therefrom, a second opening between said chambers aligned with and of smaller size than therst opening to receive a second pipe within the well pipe, said second chamber having at least one opening therefrom, and' means to close the well pipe below the lower end of the second pipe, whereby paint can be forced down from said lirst chamberv through the space between the well pipe and the second pipe and upwardly through said second pipe so as to coat the interior of the well pipe and the second pipe.

2. In a device as claimed in claim 1, means in said second opening to hold the upper end of the second. pipe and to shut off communication between the chambers.

Y 3. In a device as claimed in claim 2, means extending downwardly around the rst opening to engage the upper end of the first pipe.

4. In a device as claimed in claim l, means extending downwardly around the first opening to engage the upper end of the first pipe.

5. Apparatus for coating the interior of a well pipe which comprises, in combination, a source of compressed gas, a source of coating material, a casing having top and bottom walls and an intermediate wall dividing the casing into upper and lower expansion chambers, an opening into the bottom wall for connection with a well pipe, the horizontal cross-sectionl ofthe casing being substantially larger than such opening, an opening in the intermediate wall aligned with the irst opening to receive a smaller Well pipe, connections from said sources to the lower expansion chamber, a connection from the upper expansion chamber to the source of coating material, and means to close the well pipe below the lower end of the second pipe, whereby paint can be forced down from said first chamber through the space between the well pipe and the second pipe and upwardly through said second pipe so as to coat the interior of the well pipe and the second; pipe. i

6. In apparatus as claimed in claim 5, said last connection being arranged in the top wall of thecasing in alignment with said openings.

References Cited in the file of this patent UNITED STATES PATENTS 1,587,441 Taylor June 1, 1926 1,774,640 Dunn Sept. 2, 193() 1,812,358 Minor June 30, 1.931 2,127,728 Grant Aug. 23, 1938 2,384,192 Otis et al. Sept. 4, 1945 2,512,801 Kinney et al. June 27, 1950 

